Center for Public Health and Disasters, School of Public Health, University of California, Los Angeles, CA, USA.
BMC Public Health. 2011 Dec 13;11:922. doi: 10.1186/1471-2458-11-922.
Human infection with influenza A(H1N1) 2009 was first identified in the United States on 15 April 2009 and on 11 June 2009, WHO declared that the rapidly spreading swine-origin influenza virus constituted a global pandemic. We evaluated the seroprevalence of influenza A(H1N1) 2009 virus on a large public University campus, as well as disparities in demographic, symptomatic and vaccination characteristics of participants.
Using a cross-sectional study design, sera was collected from volunteers and then tested for the presence of antibodies to the virus using a ≥ 1:40 dilution cut-off by hemagglutination inhibition assay. In conjunction, participants were asked to complete a questionnaire allowing us to estimate risk factors for infection in this population, as well as distinguish artificially derived antibodies from naturally derived antibodies.
300 total participants were recruited and tested. 158 (52.6%) tested positive for influenza A(H1N1) 2009 via hemagglutination inhibition assay using a ≥ 1:40 dilution cut-off. 86 people (54.4%) tested positive for H1N1 but did not report experiencing symptoms during the pandemic meeting the May 2010 CDC definition of influenza-like illness. Furthermore, of those individuals who reported that they had received the H1N1 vaccine, 16% did not test positive.
Overall, 52.7% of the total study population tested positive for influenza A(H1N1) 2009. 54.4% of those who tested positive for influenza A(H1N1) 2009 using the ≥ 1:40 dilution cut-off on the hemagglutination inhibition assay in this study population did not report experiencing symptoms during the pandemic meeting the May 2010 CDC definition of influenza-like illness. 16% of those who reported receiving the H1N1 vaccine did not test positive by HAI. We also found that vaccination coverage for H1N1 vaccine was poor among Blacks and Latinos, despite the fact that vaccine was readily available at no cost.
2009 年 4 月 15 日，美国首次发现人类感染甲型 H1N1 流感病毒，2009 年 6 月 11 日，世界卫生组织宣布，这种迅速传播的猪源流感病毒构成了全球大流行。我们评估了大型公立大学校园的甲型 H1N1 2009 病毒血清流行率，以及参与者在人口统计学、症状和疫苗接种特征方面的差异。
使用横断面研究设计，从志愿者中采集血清，然后使用血凝抑制试验以≥1:40 的稀释度截点检测病毒抗体的存在。同时，要求参与者填写一份问卷，以便我们估计该人群感染的危险因素，并区分人为产生的抗体和自然产生的抗体。
共招募并检测了 300 名参与者。158 人（52.6%）通过血凝抑制试验以≥1:40 的稀释度截点检测甲型 H1N1 2009 呈阳性。86 人（54.4%）甲型 H1N1 检测呈阳性，但在大流行期间未报告出现症状，符合 2010 年 5 月疾病预防控制中心对流感样疾病的定义。此外，报告已接种 H1N1 疫苗的人中，有 16%的人检测结果呈阴性。
总的来说，研究人群中 52.7%的人甲型 H1N1 2009 检测呈阳性。在本研究人群中，通过血凝抑制试验以≥1:40 的稀释度截点检测甲型 H1N1 2009 呈阳性的人中，有 54.4%的人在大流行期间未报告出现症状，符合 2010 年 5 月疾病预防控制中心对流感样疾病的定义。报告已接种 H1N1 疫苗的人中，有 16%的人通过血凝抑制试验检测结果呈阴性。我们还发现，尽管 H1N1 疫苗免费且供应充足，但黑人和拉丁裔人群的 H1N1 疫苗接种率仍然很低。
